G'day everyone,
I'm trying to repair a Philips Bench multimeter (VOM), the PM2412, but can't get any further without the schematic. Does anyone have one available, or know where to find it online? Been looking several evenings now, but can't seem to find anything on this meter (or its relatives).
If anyone has information on this meter, it would be greatly appreciated!
Grtz,
Peter Dingemans The Netherlands.
Mike,
I've recently repaired an AVO8 and a Russian 'TSE' 4313. In both cases I needed schematics (how else to identify those burned out resistors).
The PM2412 had also some defect resistors (severely damaged by a leaking battery), so that's why the need for schematics and/or service manual.
IMHO, multimeters are difficult to service: lots of tracing, double checking, how do the wires run, how do the switches work. Hmm, even trying to understand how it works takes a few hours studying the schematic for me ;-)
Grtz,
Peter.
peter snipped-for-privacy@hotmail.com wrote in news: snipped-for-privacy@g14g2000cwa.googlegroups.com:
It's also nice to know what accuracy of resistor is needed;1%,0.1%,0.05%,along with it's value
-- Jim Yanik jyanik at kua.net
Look at virtually any VOM schematic. The resistors should all be in simple proportions for the different ranges (ie: 9 ohms,
90 ohms, 900 ohms) and as accurate as possible -- 1% or better. A schematic might diagram how the switch works, but w> Mike,Hello Mike,
I've found a schematic and the meter is repaired. A few resistors in the resistance range were damaged by battery acid and have been replaced. It's now fully operational again.
However, a generic schematic wouldn't have been of much help here, at least not to me; someone more experienced might get by, though.
BTW, there's quite some extra circuitry in the meter, to prevent damage from overvoltage/current. 3 batteries (9V for the resistance, 9V for the protection circuit and 1.5V (mono) for the lower resistance ranges).
Anyway, thanks for the tips and help in getting this meter fixed.
Grtz,
Peter.
Hello Mike,
I've found a schematic and the meter is repaired. A few resistors in the resistance range were damaged by battery acid and have been replaced. It's now fully operational again.
However, a generic schematic wouldn't have been of much help here, at least not to me; someone more experienced might get by, though.
BTW, there's quite some extra circuitry in the meter, to prevent damage from overvoltage/current. 3 batteries (9V for the resistance, 9V for the protection circuit and 1.5V (mono) for the lower resistance ranges).
Anyway, thanks for the tips and help in getting this meter fixed.
Grtz,
Peter.
I don't doubt it. Philips stuff, esp. back in the days of tubes, was bizarrely complex - mad scientist stuff.
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